There is an automatic analyzer to measure biological samples of multiple types such as blood (including serum and plasma), urine, and CSF (cerebrospinal fluid) with a sample-pipetting probe shared between the samples. It is general practice to use water to wash the sample-pipetting probe after pipetting and to subsequently rinse inner and outer walls of these automatic analyzers in order to prevent carry-over between the samples.
There conventionally have been attempts to reduce the carry-over between pipetted samples by way of improving the method for washing the nozzle and the rinse bath in which to wash the nozzle as one of the techniques for washing the sample-pipetting nozzle.
Meanwhile, the automatic analyzers have been requested to improve their analytical processing capability in recent years, and the time to pipette samples has been attempted to be shorter so as to boost overall analytical processing performance.
The time to wash the sample-pipetting nozzle also has been shortened as a result, which can lead to cases where it may be difficult to avoid carry-over unfailingly between samples following an ordinary washing operation especially in measurement items susceptible to the effects of carry-over.
The existing technologies for avoiding the carry-over between samples include a technique for setting up whether to insert a washing operation of the sample-pipetting nozzle for each measurement item and actually insert the nozzle operation before a sample is pipetted for measurement of the item in question.
Patent Document 1 discloses washing controls according to which a special washing process is performed to prevent contamination between the samples with the use of the biochemical measuring device with regard to highly sensitive immunological items if a specific analysis item is contained in individual samples in a device structure having a device for measuring biochemical items connected with a device for measuring immunological items.